It is increasingly apparent that molecular triplet states play important roles in biology, genetics, and medicine. The mutagenic and lethal effects of ultraviolet irradiation on bacteria have been traced to lesions in DNA molecules, reactions which, at least in vitro, involve triplet states of DNA bases. Also, the triplet state of chlorophyll has been convincingly implicated in the mechanism of photosynthesis. A fundamental study of the chemistry of molecular triplet states therefore could provide information important to key biological processes. This study will involve the methods of generation, properties, and chemical reactions of trimethylene-methanes, a class of ground state triplet molecules.